Exhaust manifold



May 1, 1945. c. R. sass ET AL I EXHAUST MANIFOLDS Filed Oct. 10,

1941 2 Sheets-Sheet l INVENTORS 'flVDE IPQf/II AND BY l K [.JTEElE May1, 1945. ckR. EISS ETAL EXHAUST MANIFOLDS 2 Sheets-Sheet 2 Filed Oct.10, 1941 INVENTOR R. EIEE-i. ERICK I-STEELE ATTEIRNE Patented May 1,1945 EXHAUST MANIFOLD Clyde R. Eiss,.Bufl?alo, and Frederick I. Steele,Kenmore. N. Y., assignors to Curti'ss-Wrig'ht Corporation, a corporationof Delaware Application October 10 .5 Claims.

This inventionrelates to exhaust manifolding systems, particularly .asapplied to radial cylinder aircraft engines.

An object 'of the invention is to provide an exhaust pipe arrangementfor radial cylinder engines whereby minimum exhaust back pressure iscaused and. wherein simplicityin manufacture is an importantconsideration. A further object is to provide a radial cylinder engineexhaust system wherein the exhaust is led to the atmosphere through aplurality of exhaust nozzles arranged in tandem, one of such exhaustnozzles serving not more than two of the engine cylinders. A furtherobject of the invention isto provide an exhaust manifold system andexhaust nozzles therefor which are easy to assemble upon and todisassemble from an aircraft engine when installed inan aircraft.

Further :objects of the invention will become apparent in reading theannexed description in connection wtih the drawings, in which:

Fig. 1 is a rear elevation of a radialengine exhaust pipe system;

Fig. 2 is a perspective view of an exhaust pipe and a nozzle therefor; Hl

Fig. 3 is a front elevation ofa pipe applied to an exhaust nozzle;

Fig. 4 is aside elevation of an exhaust system as applied to thelefthand .side of a radial engine; and

Fig. 5 is a side elevation of an exhaust system as applied to therighthand side of a radial engine.

Single row radial cylinder engines having a four-stroke cycle normallycomprise an odd number of cylinders, and a nine-cylinder engine has beenchosen for illustration in Fig. l. The cylinders are numbered from I lto IS in a clockwise direction, each cylinder having an exhaust portdesignated b the cylinder number primed. The firing order of an engineof this type is H, l3, [5, ll, I9, l2, l4, l6, and Ill, so that any twoadjacent cylinders exhaust their products of combustion approximatelyone crankshaft revolution apart. In older type of manifolding, it wasusual 7 194 1, Serial No. 414,432

nected .intoa tapered manifold so that a single manifold outletdischargethe eidiaust gas from all of the engine cylinders. Suchtaperedmanifolds were expensive and somewhat difficult to construct andfurthermore, were so bulky as .to bedifficult of application to anengine installation.

- In the present'system, we utilize a separate manifold for each 1 pairofradjacent cylinders; for instance, cylinders l2 and i3 areservedwby acommon manifold 21 of uniform "diameter throughout its length, said.manifold having its outlet end disposed at 22, .nearxthe side of the,

engine. Cylinders M and it are served by a manifold at-of uniformdiameter throughout its length, theoutlet 24 thereof terminating intandem relationship with the outlet 22 of the pipe 2|. These two pipes2i and 23 serve the four A pipe 25, of uniform diameter, is connected tothe exhaust ports of cylinders II and I9, such pipe having its outletend disposedon the left side of the engine at 26. Cylinders i6 and H areserved by a pipe 21 of uniform l-diameterthroughout its length, havingits outlet 28 disposedin tandem relation Withrespect to the outlet 26.Theodd cylinder 18 is served by a single exhaust pipe 29 whose outlet 30is also disposed in tandem relation. with respect tothe outlets 2t and28. It will be seen that each exhaust-pipe serves two adjacent cylindersand the exhaust discharges from such cylinders occur approximately onecrankshaft revolution apart and therefore do not overlap. Thus, eachpipe may be made with a diameter appropriate for the discharge of but asingle cylinder and minimum back pressure will be attained. I

One each side of the installation, is a brace member not secured to theengine mounting or cowling structure, the righthand brace member beingnumbered 32 and the lefthand brace memher being numbered 33. The member32 carries two exhaust nozzles 34 and 35 respectively connected to theexhaust pipes 23 and 2!. The lefthand member 33 carries three nozzles36, 31 and 38, respectively connected to the exhaust pipes 21, 25 and29. These nozzles, as typically shown in Fig. 2, may be rearwardlydirected to provide jet effect for the issuing exhaust gases and by thetandem arrangement of the several sets of nozzles, minimum aerodynamicdrag results. These nozzles project beyond the profile of the enginecowling 40.

The several nozzles may be made as a unit assembly with their members 32or 33 and as shown in Fig. 3, the inner end of each nozzle comprises areceptacle 42 within which the end of the exhaust pipe such as 23 may beinserted, as shown in Fig. 3.

Where disassembly of the system is required, the cowling 40 is firstremoved. Thereafter, the members 32 and 33 may be removed as a unit withthe exhaust nozzles, leaving the end of the several exhaust pipes freeof any structural support. Thereafter, each pipe may be removed merelyby detaching it from the cylinders which it serves. Preferably, a slipjoint such as is shown at 44 is inserted in each exhaust pipe unitbetween the two cylinders which serves to allow for independentexpansion and contraction of the engine cylinders and to avoid breakageof the exhaust pipe elements.

By the exhaust pipe system disclosed, a low drag, eflicient exhaustnozzle system is provided analogous to that used on in-line engines. Ithas been found that the weight and bulk of the system disclosed comparesfavorably with the unitary manifold arrangements of the prior art.

While we have described our invention in detail in its present preferredembodiment, it will be obvious to those skilled in the art, afterunderstanding our invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Weaim in the appended claim to cover all such modifications and changes.

We claim as our invention:

1. In combination with a multi-cylinder radial engine wherein thecylinders have an alternate firing order and wherein each cylinder hasan exhaust port, an exhaust pipe for each pair of adjacent cylinderscommunicating with the exhaust ports thereof, the several pipes for theseveral pairs of cylinders being extended to lie in tandem relation attheir outlet ends, and a member on opposite sides of the engine, each ofsaid members having a plurality of tandem arranged exhaust nozzles witheach one of which one of said pipes engages.

2. In combination with amulti-cylinder radial engine, the enginecylinders having an alternate firing order and each cylinder having anexhaust port, a plurality of exhaust pipes on each side of the engineeach pipe communicating with the ports of not more than two adjacentcylinders,

the several pipes on each side of the engine having their outlet ends intandem relation, 2. structural member on each side of the engine, andtandem arranged exhaust nozzles projecting outwardly from each memberwith each of which one of said pipes is connected.

3. In combination with a multi-cylinder radial engine, the enginecylinders having an alternate firing order and each cylinder having anexhaust port, a plurality of exhaust pipes on each side of the engineeach pipe communicating with the ports of not more than two adjacentcylinders, the several pipes on each side of the engine having theiroutlet ends in tandem relation, cowling embracing said engine, and aunit assembly of tandem arranged exhaust nozzles projecting from saidcowling with each of which one of said pipes is connected within theconfines of said cowling.

4. In combination with a radial cylinder engine having an odd number ofcylinders and alternate firing order, whereby adjacent cylinders exhaustnearly one crankshaft revolution apart, each cylinder having an exhaustport, a plurality of exhaust pipes each being connected to the exhaustports of two only adjacent cylinders, whereby the flow of exhaust gasthrough each pipe is intermittent and substantially non-overlapping, aidpipes being disposed around portions of the engine and having theiroutlet ends terminating at one side of the engine in tandem relation,and a unitary exhaust nozzle assembly comprising a plurality of tandemarranged nozzles with each one of which one said pipe is connected.

5. In an internal combustion engine having a plurality of radiallyarranged cylinders, said cylinders having an alternate firing order, acowling embracing the engine, a plurality of exhaust pipes eachconnected to a pair of adjacent cylinders, and a pair of integralassemblies disposed on oppositesides of said engine and supported withinand independently of said cowling, each assembly comprising a plurality'of tandem disposed discharge nozzles extending through said cowlingwith each of said nozzles connected to and in communication with but oneof said exhaust pipes.

CLYDE R. EISS. FREDERICK I. STEELE.

